Fluidic valves and manifolds are in common use today in technologies requiring complicated control of the flow of gasses and/or fluids in fields such as medical processing equipment and the like. Essentially, the manifolds or valves comprise solid blocks, often of plastic material, having an internal maze of interconnected passageways, channels, ports and cavities, which, if not contained within a module, would require a substantially larger and more complicated assemblage of tubes, hoses, receptacles and chambers to be assembled. Many of the channels are not linear but rather are arcuate. Some intersect at angles and are three dimensional.
It is virtually impossible to drill a curved channel or passageway wholly within a solid block. However, a curved channel can be milled in a surface of a block and that surface can subsequently be joined to a surface of another block to produce a curved channel. Likewise, some passageways have to be at least an inch or more in length and are very narrow, often the size of a needle. Drilling such passageways in plastic, such as acrylic, while maintaining close tolerances, is extremely difficult. Accordingly, fluidic valves or manifolds have been made by machining various passageways, ports, openings and conduits in one surface of a plastic block, and then attaching another block to that surface whereby the passageways are then located in the interior of the combined blocks. As an alternative, occasionally both halves of the combined blocks are machined with mirror-image configurations in their mating surfaces which surfaces subsequentially are brought together into intimate contact. This invention is directed to the process of bonding such surfaces together to form a module and to make fluidic valves and manifolds.
It is essential that the contacting surfaces be airtight, particularly if the module is to be used for valving or conducting pressurized fluids or gasses. It is obvious that the component halves could be screwed or bolted together but this causes stress concentration and only assures tightness in the areas immediately surrounding the screw or bolt. Furthermore, since the modules are frequently small, room is not available for locating screws or bolts which would otherwise interfere with the passageways or valves.
It would also be obvious to clamp the members together but this adds to the bulk and would out down on the visibility.
Another method which immediately comes to mind as an expedient for securing together the component halves, is through the use of glue or cement. This is unacceptable for a number of reasons. Cements can contaminate the gasses or fluids flowing through the passageways in the modules. Furthermore, if not extremely carefully applied, cement can leak into and partially or completely block the passageways. Furthermore, gluing or cementing frequently results in the presence of bubbles which can be detrimental to the optical properties of the molecules. Also, in many instances, it is not only desirable but mandatory that the passageways be readily visible for inspection of the passage of fluids or gasses. Glue or cement can change the index of refraction between the two component halves or render the interface opaque.
It is thus an object of the present invention to be able to secure two or more component portions of a module together without the use of screws, glues or any third element.